JP4688993B2 - Volume reference device - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a volume reference device that delivers a fixed amount of fluid, such as used when inspecting an instrumental difference of an integrating volume meter.
[0002]
[Prior art]
Conventionally, in order to check the accuracy of an integrated volume meter such as a water meter, a fixed amount of fluid (water in the case of a water meter) is sent to the integrated volume meter, and the feed amount and the value indicated by the integrated volume meter are In general, an integrated volume meter automatic inspection device (or an integrated volume meter automatic inspection method) for determining whether or not the integrated volume meter has a normal accuracy by comparing the above is widely performed. In this inspection, it is assumed that the feed amount from the volume reference device has an accurate value, and if the feed amount is a general cylindrical piston, the movement amount of the piston and the cross-sectional area of the piston Can be calculated.
[0003]
In such a volume reference device, when the fluid leaks from one internal chamber to the other internal chamber through the sliding portion (for example, leakage due to wear in the sliding portion), the leakage Since the amount becomes an error, the actual discharge amount is different from the assumed discharge amount. Therefore, if there is a leak inside the integrated volume meter as described above, it is difficult to accurately inspect the integrated volume meter, so it is necessary to replace the volume reference device. There has been a demand for a volume reference device that can easily detect leakage.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the present invention is a volume reference device that can accurately discharge a fixed amount of fluid, and provides a volume reference device that can easily detect an abnormality when the discharge amount is different from a set value. There is to do.
[0005]
[Means for Solving the Problems and Effects of the Invention]
In order to solve the above problems, the volume reference device of the present invention is
A hollow cylinder, and a cylinder into which fluid is sucked into the hollow portion;
A piston slidably provided in the cylinder;
A piston rod connected to the piston for moving the piston;
Two cylinder inner chambers are formed in the cylinder and divided by the piston and change in internal volume by movement of the piston. The cylinder is formed in a cylindrical shape and slides on the piston. A volume reference device that fits in a possible manner and discharges a predetermined amount of fluid provided in the cylinder inner chamber by movement of the piston,
A first liquid passage that opens to the outer peripheral surface of the piston and extends from the outer peripheral surface toward the center of the piston;
A second liquid passage that communicates with the first liquid passage and extends along the longitudinal direction of the piston rod, and is guided to the outside of the cylinder.
Fluid leaking from one internal chamber of the two cylinder internal chambers to the other internal chamber through the clearance between the piston and the inner wall of the cylinder through the first and second liquid passages. By discharging to the outside, it is possible to detect poor piston seals,
At least two seal members that seal the inner wall of the cylinder and prevent leakage of fluid from the two cylinder inner chambers are provided annularly along the outer periphery of the piston,
Between the two seal members on the outer wall of the piston, a guide groove for guiding the leaked fluid is formed in the circumferential direction of the piston, and the guide groove has a tapered side portion extending toward the inner wall of the cylinder. And the first liquid passage communicates with the bottom of the guide groove provided on the narrowing side of the taper.
[0006]
As described above, the fluid leaking through the clearance between the piston and the inner wall of the cylinder is discharged to the outside of the cylinder through the first and second liquid passages, thereby detecting a poor seal of the piston. By making it possible, the leakage fluid can be confirmed outside the cylinder, and abnormality inside the cylinder can be detected. If fluid leakage is detected, it will be found that the discharge amount is different from the assumed value (ie, the amount calculated by the amount of movement of the piston, etc.). I can know. In other words, a volume reference device in which no leaked fluid is confirmed can deliver fluid with high accuracy, and thus contributes to the provision of a highly accurate integrating volume device.
[0007]
Further, the sliding portion is provided with an outlet for leaking fluid, and a liquid passage formed in the piston is provided, and a pipe formed as the liquid passage causes one internal chamber in the two cylinder internal chambers to the other inside. Leaked fluid that has leaked to the chamber side through the gap of the sliding portion may be led out of the cylinder. In this way, by forming the liquid passage having the outlet at the sliding portion with the cylinder inner wall, the fluid leaking through the sliding portion can be led out at the outlet, and the liquid passage is externally provided. The leakage fluid can be guided to the outside of the cylinder by connecting to the cylinder, and whether or not there has been leakage can be confirmed outside the cylinder (thus, if the leakage fluid is confirmed outside the cylinder, accurate discharge can be performed. It turns out not to have been done).
[0008]
The piston rod may be provided with a discharge port for the liquid passage, and a discharge fluid detection means for detecting that the leaked fluid has been discharged may be provided at the discharge port. In this way, by providing the discharged fluid detection means at the discharge port formed in the liquid passage, it is possible to easily detect that the fluid has been discharged, and to know the abnormal discharge. Further, the discharged fluid detecting means can be provided with a discharge amount measuring means for measuring the discharge amount of the leaked fluid, and in this way, the discharged fluid amount can be measured, and the discharged amount is measured as the discharge amount. It can be used as an index of abnormality. For example, when the discharge amount indicates a certain amount or more, it may be determined that the discharge amount is abnormal.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. FIG. 1 shows a volume reference device 5 which is an example of the present invention. The volume reference device is provided with a cylinder 18 formed in a cylindrical shape and a piston 16 slidably fitted in the cylinder 18. A piston rod 20 is fixed or integrally formed with the piston 16, and the piston 16 slides inside the cylinder 18 in response to the movement of the piston rod 20. Further, the internal chamber of the cylinder 18 formed in a hollow shape is divided into two internal chambers (a first cylinder internal chamber 30 and a second cylinder internal chamber 32) by the piston 16, and each internal chamber has a fluid. Passage holes 34 and 36 are formed to allow the fluid in the region to be introduced and introduced. In the cylinder internal chamber on the side where the internal volume is reduced by the movement of the piston 16, the internal fluid flows out from the fluid passage hole, and the external fluid flows into the internal chamber on the side where the internal volume is increased through the fluid passage hole ( It is configured as a so-called reverse cylinder). In the two cylinder inner chambers formed as described above, the gap passes through the sliding portion between the piston 16 and the cylinder 18 from one inner chamber to the other inner chamber side (for example, from the inner chamber 30 to the inner chamber 32). Thus, a liquid passage for discharging the leaked fluid to the outside is provided as leaked fluid detection means for detecting that the fluid has leaked. Hereinafter, the leakage fluid detection means will be described.
[0010]
FIG. 2 shows an enlarged view of the sliding portion between the piston 16 and the cylinder 18. The piston 16 formed in a columnar shape is provided with a guide groove 17 formed in the circumferential direction thereof, and on both sides of the guide groove 17 as a seal member for sealing a sliding portion between the piston 16 and the cylinder 18. The sliding ring and the O-ring are provided in a state of being fitted in the grooves, respectively, and function as sealing members. Further, as a first seal member that is located on the first cylinder inner chamber 30 side and receives the pressure of the fluid in the first cylinder inner chamber 30 (FIG. 1) to prevent fluid leakage from the inner chamber. The O-ring 12a and the second cylinder inner chamber 32 side which are located on the second cylinder inner chamber 32 side and receive the pressure of the fluid in the second cylinder inner chamber 32 to prevent fluid leakage from the inner chamber An O-ring 12b is provided as a second seal member located at the position. The sliding rings 14a and 14b provided beside the O-rings 12a and 12b have a function of reducing the pressure generated in the O-ring from the cylinder inner chamber. These seal members prevent fluid leakage from the respective cylinder inner chambers to the sliding portions and the other inner chambers, thereby enabling discharge of the metered fluid from the volume reference device.
[0011]
When such a seal member is functioning normally, that is, when there is no seal failure, the discharge amount can be calculated from the movement amount of the piston as the decrease amount of the internal volume in the cylinder inner chamber on the discharge side. When a seal failure has occurred due to wear of the seal member or the like, an error occurs between the calculated amount and the actual discharge amount, making it difficult to accurately grasp the discharge amount. Therefore, when a leak occurs from the sliding portion due to a seal failure, a fluid lead-out path for discharging the leaked fluid to the outside is formed as follows so that the leak can be confirmed outside.
[0012]
As shown in FIG. 2, the end opening of the first liquid passage 10 is located at a position sandwiched between seal members on both sides (the first cylinder inner chamber 30 side and the second cylinder inner chamber 32 side) of the outer wall of the piston 16. , And the opening serves as a further outlet for the leaked fluid stored in the guide groove 17. Further, a guide groove 17 for guiding leakage fluid in the circumferential direction of the piston 16 is formed between the two seal members (O-rings 12a, 12b) on the outer wall of the piston 16, and the guide groove 17 has a groove cross section that is a cylinder. Side portions are formed in a tapered shape that expands toward the inner wall direction, and the opening of the first liquid passage 10 is located at the bottom of the guide groove 17. By forming the taper-shaped cross section in this way, the leaked fluid easily enters the guide groove 17. A lead-out portion for leaking fluid is formed by including the guide groove 17 and the opening. The cross-sectional shape of the guide groove is not limited to this, and various shapes such as a square shape and a U-shape can be used, and the first liquid passage 10 is formed to communicate with at least a part of these guide grooves. It only has to be. Further, as shown in FIG. 1, the first liquid passage 10 is formed with a pipe line in the radial direction of the piston 16, communicates with the first liquid passage 10, and has a direction perpendicular to the axial direction of the piston rod 16. By providing the second liquid passage 40 (FIG. 1) that is changed and has a discharge port outside, leakage fluid can be discharged to the outside. As described above, the leakage fluid outlet passage is formed by having the first liquid passage 10 and the second liquid passage 40. Note that the direction of the conduit of the leaking fluid outlet passage is not limited to such a direction, and it is sufficient that the sliding portion has an outlet port and a discharge port outside the cylinder. For example, the direction may be changed in a curved manner at a corner (for example, the corner of the communication portion between the first liquid passage 10 and the second liquid passage 40) without changing the direction at a right angle.
[0013]
As described above, by forming the guide groove 17 that guides the leaked fluid in the circumferential direction, the leaked fluid can easily move in the guide groove 17 and easily enter the outlet port. When the groove 17 is not formed and the piston outer wall and the cylinder inner wall are close (or in contact) between the seal members (O-rings 12a, 12b) on both sides, the seal member on the side that reduces the internal volume When excessive pressure is generated and fluid leaks from the contact portion between the seal member and the cylinder or piston, it is difficult to move the leaked fluid in the circumferential direction of the piston between the seal members, and the leaked fluid becomes the first outlet. This makes it difficult for leaked fluid to enter the opening of the liquid passage 10. In addition, when the amount of leaking fluid is too large, etc., when excessive pressure is generated in the other seal member (the seal member on the cylinder inner chamber side that increases the internal volume) due to the leaked fluid, the other inner chamber further There is a possibility of leakage. When the above configuration is adopted, it is extremely less likely that the leaking fluid further leaks into the cylinder inner chamber on the side where the internal volume is increased. The liquid passages 10 and 40) are easily discharged to the outside.
FIG. 3 illustrates the movement of the piston 16 and the accompanying internal fluid leakage. As shown in FIG. 3A, when the piston 16 moves to the second cylinder inner chamber 32 (see FIG. 1) side (in the direction of the arrow 15a), the pressure inside the second cylinder inner chamber 32 increases. The fluid is discharged from the fluid inlet / outlet port 36 (FIG. 1). At this time, when the sliding portion (for example, the contact portion between the O-ring 12b and the inner wall of the cylinder) is not sufficiently adhered (that is, when a seal failure occurs), the internal pressure of the second cylinder inner chamber 32 is reduced. If it is extremely large, the internal fluid leaks as indicated by the arrow 13a, and the fluid accumulates in the guide groove 17 portion. The leaked fluid is guided by the first liquid passage 10 communicating with the guide groove 17 (moves in the direction of the arrow 13b) and discharged outside the cylinder.
[0015]
As shown in FIG. 3B, the same applies when the piston 16 moves to the first cylinder inner chamber 30 (FIG. 1) (in the direction of the arrow 15b), and the sliding portion (for example, the O-ring 12a and the cylinder) In the case where the close contact (in contact with the inner wall) is insufficient (seal failure), the internal fluid leaks from the first cylinder inner chamber 30 as simply indicated by the arrow 13c, as described above. The leaked fluid is led out to the outside by the first liquid passage 10. In this way, by forming the first liquid passage 10 having the opening serving as the outlet in the sliding portion with the cylinder inner wall, the fluid leaking through the sliding portion can be led out to the outlet. In addition, since the fluid passage is connected to the outside, the leaked fluid can be guided to the outside of the cylinder and whether or not there is a leak can be confirmed outside the cylinder (that is, when the leaked fluid is confirmed outside the cylinder). It turns out that the correct ejection was not performed.
[0016]
In addition, you may make it provide the discharge fluid detection means which detects that the leaking fluid was discharged | emitted in the discharge port of the fluid outlet path formed in the piston rod 20. FIG. As the discharged fluid detection means, the discharge port may be visually confirmed, or a discharge amount measuring means such as a measuring cylinder for measuring the discharge amount of the leaked fluid may be provided. By visually confirming the discharge of the leaked fluid, the apparatus configuration can be simplified and the inspection can be easily performed. Further, by providing a discharge amount measuring means such as a graduated cylinder, the discharged fluid amount can be measured, and the discharge amount can be used as an indicator of abnormality in the discharge amount. For example, if the discharge amount measured by the discharge amount measuring means shows a value greater than or equal to a certain amount, it may be determined that the discharge amount from the cylinder is abnormal. May be determined to be abnormal.
[0017]
In addition, a humidity sensor that detects that the fluid has passed as fluid passage detection means in the first and second liquid passages, or a portion where leaked fluid such as a discharge port passes or a portion where the discharged fluid is accumulated), A flow rate sensor, a flow rate sensor, or the like (collectively referred to as a fluid passage detection sensor) may be provided. In particular, if a sensor (for example, an electromagnetic flow meter, an ultrasonic current meter, a correlation current meter, a Doppler current meter, etc.) that detects a minute fluid passage is provided, the sensing accuracy is increased. By providing such an electromagnetic flow meter or the like in the portion through which the leaking fluid passes, it becomes possible to measure a minute flow rate and automatically detect whether or not the leaking fluid has occurred.
[0018]
FIG. 4 shows an essential part of an inspection system for an integrated volume meter that has been generally performed as an embodiment of the present invention, and FIG. 5 shows a circuit diagram of a pipe configuration example. . The outline of this inspection system will be described. A fixed amount of fluid is discharged from the volume reference device 5 and connected in series (herein, the series connection means that the inlet of another integrating volume meter 2 is connected to the outlet of the integrating volume meter 2. By connecting, a certain amount of fluid is sent to the inspection fluid flow path system 45 constituted by the integrating volume meter 2 (which is a connecting method for allowing fluid to pass through all the integrating volume meters in one pipe line). . Since a rotation index (not shown) provided in each integrating volume meter rotates at a rotation speed corresponding to the flow rate by the passage of fluid, the rotation index is sensed by a rotation detection means such as an optical sensor.
[0019]
This rotation index is an octagonal pyramid-shaped rotator whose rotation speed is set according to the flow rate of the fluid passing through the integrating volume meter. Light is applied to the slope of this rotation index, and the reflected light is received by the light receiving element. The output fluctuation pulse of the light receiving element generated according to the rotation of the rotation index is counted, and the passage flow rate is obtained by converting the flow rate based on that value, and this passage flow rate is compared with the discharge amount by the volume reference device. The instrumental volume meter is inspected. The rotation indicator is not a rotating body, but may be a rotation display unit that is displayed on a liquid crystal display or the like and the number of rotations is set according to the passing flow rate. The rotation display unit is sensed by an optical sensor such as a CCD camera and image processing is performed. A method for calculating the rotation may be used. In addition, since the measuring method of the flow volume which passes the integrating | accumulating volume meter using such a rotation parameter | index is generally used for the instrumental difference inspection, since it is well-known, it abbreviate | omits for details.
[0020]
Then, a certain amount of fluid discharged by the integrating volume meter passes through the inspection fluid channel system 45, and each rotation index that rotates in response to the passage is individually detected by a sensor 41 as a rotation detecting means, Furthermore, the passing flow rate is calculated for each integrated volume meter, and it is compared whether there is any difference from the delivery flow rate. At this time, if the integrated volume meter shows a value outside the reference range (for example, a case that greatly deviates from the error range to be considered), the integrated volume meter will be removed as a defective product indicating an abnormal value. .
[0021]
Incorporating the volume reference device 5 having the characteristics as in the present invention into the generalized volumetric meter inspection system as described above to use a volume reference device in which internal leakage occurs. Therefore, only a highly accurate volume reference device can be used. Therefore, an accurate amount of fluid can be sent to the integrating volume meter, and the accuracy of inspection becomes extremely high. In addition, it is possible to easily determine whether or not the quality as a volume reference device is maintained, and it is possible to know an appropriate replacement time, thereby contributing to the provision of a high-quality integrating volume meter.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a volume reference device of the present invention.
2 is an enlarged cross-sectional view showing the main part of FIG.
FIG. 3 is an explanatory diagram illustrating the flow of a leaking fluid.
FIG. 4 is an explanatory diagram showing an example of use of the volume reference device of the present invention.
FIG. 5 is an explanatory diagram for simply explaining a pipeline and a device configuration.
[Explanation of symbols]
2 Integrating volume meter 5 Volume reference device 10 First liquid passage 12 O-ring (seal member)
14 Sliding ring 16 Piston 18 Cylinder 20 Piston rod 30 First cylinder inner chamber 32 Second cylinder inner chamber 34 Fluid inlet / outlet 36 Fluid inlet / outlet 40 Second liquid passage

Claims (3)

A hollow cylinder, and a cylinder into which fluid is sucked into the hollow portion;
A piston slidably provided in the cylinder;
A piston rod connected to the piston for moving the piston;
Two cylinder inner chambers are formed in the cylinder and divided by the piston and change in internal volume by movement of the piston. The cylinder is formed in a cylindrical shape and slides on the piston. A volume reference device that fits in a possible manner and discharges a predetermined amount of fluid provided in the cylinder inner chamber by movement of the piston,
A first liquid passage that opens to the outer peripheral surface of the piston and extends from the outer peripheral surface toward the center of the piston;
A second liquid passage that communicates with the first liquid passage and extends along the longitudinal direction of the piston rod, and is guided to the outside of the cylinder.
Fluid that leaks from one internal chamber of the two cylinder internal chambers to the other internal chamber through a clearance between the piston and the inner wall of the cylinder through the first and second liquid passages. By discharging to the outside, it is possible to detect poor piston seals,
At least two seal members that seal the inner wall of the cylinder and prevent leakage of fluid from the two cylinder inner chambers are provided annularly along the outer periphery of the piston,
Between the two seal members on the outer wall of the piston, a guide groove for guiding the leaked fluid is formed in the circumferential direction of the piston, and the guide groove has a tapered side portion extending toward the inner wall of the cylinder. The volume reference device is characterized in that the first liquid passage communicates with the bottom of the guide groove provided on the narrowing side of the taper.   A discharge port of the second liquid passage is formed outside the cylinder of the piston rod, and a discharge fluid detection means for detecting that the leaked fluid is discharged is provided in the discharge port. The volume reference device according to claim 1, wherein   The volume reference device according to claim 2, wherein the discharge fluid detection unit includes a discharge amount measurement unit that measures a discharge amount of the leaked fluid.

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